In the area of hot rolling technology, defined cooling of the rolling stock in a cooling section is of great significance for allowing desired material properties (for example a microstructure) of the rolling stock running out from the cooling section to be reliably set. Consequently, correctly timed application of the coolant to the rolling stock in terms of location and quantity is of decisive significance for properly implemented cooling of the rolling stock in the cooling section. Consideration of the valve-specific characteristics is required for this. The valve-specific characteristics here particularly comprise a switch-on delay and a switch-off delay. In operational practice, the valve-specific characteristics change during operation. For example, the delays may be influenced by wear. Furthermore a valve-related average flow rate often also varies while operation is in progress. This variation may be caused, for example, by contaminants.
To the knowledge of the applicant, the determination of the switch-on delay and switch-off delay of one of the valves (known as dead time measurements) is currently carried out manually (by using a stopwatch). This involves the operator of the cooling section starting the stopwatch at the same time as a control signal for opening the respective valve occurs. He stops the stopwatch when, in his subjective judgement, the full amount of water is flowing onto the rolling stock or onto the roller table. This measured time is then considered to be the switch-on delay. In an analogous way, the operator of the cooling section determines a switch-off delay for the respective valve. The average amount of coolant that flows through the respective valve per unit of time is determined in the prior art by means of gaging the amount in liters. This measurement is very laborious and time-consuming and is generally only performed rarely. It generally requires auxiliary equipment adapted to the installation, such as for example water tanks.
In particular on account of the only relatively rare detection of the average flow rates, the actual valve-specific characteristics often no longer coincide in practice with the parameterized characteristics on the basis of which the valve-specific opening times and valve-specific closing times are determined in a cooling section model. Therefore, application of the coolant to the rolling stock is less than optimal, at the same time bringing about the effect that the rolling stock does not in fact end up with the desired product properties.